(1) Field of the Invention
The present invention relates to a bidirectional semiconductor device which enables a one-directional circuit such as a first-in first-out (FIFO) memory to carry out bidirectional data transmission.
(2) Description of the Related Art
Generally, a two-port buffer (chip) such as a FIFO memory, a last-in first-out (LIFO) memory, and a shift register has an input port and an output port, thereby establishing a one-directional data transmission from the input port to the output port. In the prior art, terminals corresponding to these input ports and output ports are fixed, and if one-directional FIFO's having these fixed input/output pins are used for a bidirectional data transmission, at least two FIFO's are required. As a result, the number of chips on a printed board is increased to increase the area of the board occupied by mounting the chips thereon (hereafter, board occupied area), and in addition, the input/output (I/O) connections on the printed board become complex. Note that the complexity of the I/O connections also increases the mounting density of the printed board because of the area occupied thereby, and deteriorates the electrical characteristics of the device due to the stray capacity of the connections.